As I wrote in my previous article, the operation of electric vehicles (EVs) is relatively “clean,” especially when powered by renewably generated electricity. However, the emissions from simply operating a vehicle are not the only environmental concern. For EVs, what makes them go is the battery, a piece of highly refined technology that comes with its own environmental impacts.
A recent study, led by biosystems engineering researcher Christopher W. Tessum and published by the National Academy of Sciences, examined the air-quality impacts of light-duty vehicles on human health in the US. Tessum and colleagues compared the emissions by traditional gasoline-powered vehicles with various alternatives, including battery electric vehicles (BEVs).
In the analysis, Tessum considered the lifecycle air-quality impacts of BEV battery production and found their impacts relatively small in terms of population mortalities and externality damages. For example, for an EV powered by an average US power-generation mix, battery production accounted for only about 10 percent of lifecycle emissions of fine particulate matter (PM2.5, or particles of 2.5 microns or less).
Tessum admitted that his team's results showed a smaller impact from battery production than previous research by Jeremy J. Michalek and colleagues did. Tessum pointed out that Michalek assumed that “processes upstream from EV battery manufacturing are colocated with automobile manufacturing facilities.” However, according to Tessum, “production of copper and other raw materials for batteries occurs far from people,” so the potential harm is reduced. For example, he said, “copper ore smelting, which causes the majority of battery production SO2 emissions, mainly occurs in the sparsely populated southwestern United States.”
However, US air-quality impacts are not the only environmental concerns raised about EV battery production. Not all materials and components used in lithium-ion batteries are produced in the US, and they can have environmental impacts other than air pollution.
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Graphite, for example, is a key material used for negative electrodes in Li-ion batteries. Researchers estimate that a BEV battery requires about 50 kilograms of graphite. By far, graphite is mined in China, according to the US Geological Service (USGS). The agency says batteries are the fastest-growing market for graphite, increasing at between 15 and 25% growth per year.
In 2011, the Chinese government began shutting down graphite mines for environmental and resource protection. Stricter controls were imposed to prevent a pollution problem called “graphite rain.” USGS explains that “dust emissions from the mining of crystalline flake graphite had become a major issue, and although graphite is inert and not harmful, the air pollution from dust had become a problem to local residents and farmers.”
Bloomberg New Energy Finance reports that the environmental problems in China have depressed graphite production and pushed up prices. Aside from illuminating the concerns about graphite rain, Bloomberg also points to problems arising from the hydrochloric acid used to process raw graphite. Poor disposal practices have resulted in the release of the corrosive chemical into wastewater.
As with any manufactured product, end-of-life disposal is a concern with EV batteries. Since the EV market is comparatively young, relatively few batteries have reached mortality. However, that will change over the next 15 to 20 years. The US Department of Energy says processes for battery recycling are under development, including smelting processes to recover basic elements or salts, and direct recovery, which involves separating materials for re-use, is being investigated.
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Even though old batteries might lose their suitability for electric cars, some experts point out that they could still be useful for other purposes. A study by the Mineta National Transit Research Consortium explored the feasibility of remanufacturing Li-Ion batteries for re-use in vehicles, repurposing them for stationary uses, and disassembling them to recover materials. “Remanufacturing was shown to be profitable,” the organization determined, “primarily due to the avoided costs of producing new batteries when a remanufactured battery could be used instead.” While the economic feasibility of repurposing and recycling batteries was harder to pin down, the report stressed that “recycling can support closed-loop supply chains reusing materials in the production of new batteries as well as supporting the principles of environmentalism and sustainability.”
Obviously, the environmental impacts of Li-Ion EV battery production are not zero. However, battery efficiency is improving and new battery technologies are in the works. These improvements could make BEVs even more attractive compared to conventional gasoline vehicles. A future article will discuss trends in EV battery technology and how they might affect the environmental picture.
Al Bredenberg is a writer, analyst, consultant, and communicator. He writes about technology, design, innovation, management, and sustainable business, and specializes in investigating and explaining complex topics. He holds a master's degree in organization and management from Antioch University New England. He has served as an editor for print and online content and currently serves as senior analyst at the Institute for Innovation in Large Organizations.